Buggy code:
public final class WalaPointsToUtil { private WalaPointsToUtil ( ) { } public static final < T > OrdinalSet < T > unify ( final OrdinalSet < T > a , final OrdinalSet < T > b ) { } private static class DelegatingMethodTargetSelector implements MethodTargetSelector { private final MethodTargetSelector parent ; private final MethodTargetSelector child ; private final AnalysisScope scope ; public DelegatingMethodTargetSelector ( final MethodTargetSelector parent , final MethodTargetSelector child , final AnalysisScope scope ) { } @ Override public IMethod getCalleeTarget ( CGNode caller , CallSiteReference site , IClass receiver ) { } @ Override public String toString ( ) { } } public static CallGraphBuilder makeRTA ( final AnalysisOptions options , final AnalysisCache cache , final IClassHierarchy cha , final AnalysisScope scope ) { } public static CallGraphBuilder makeContextFreeType ( final AnalysisOptions options , final AnalysisCache cache , final IClassHierarchy cha , final AnalysisScope scope , final ContextSelector contextSelector , final SSAContextInterpreter contextInterpreter ) { } public static CallGraphBuilder makeContextSensSite ( final AnalysisOptions options , final AnalysisCache cache , final IClassHierarchy cha , final AnalysisScope scope , final ContextSelector contextSelector , final SSAContextInterpreter additionalContextInterpreter ) { if ( options == null ) { throw new IllegalArgumentException ( "options<seq2seq4repair_space>is<seq2seq4repair_space>null" ) ; } { MethodTargetSelector oldMethodTargetSelector = options . getMethodTargetSelector ( ) ; Util . addDefaultSelectors ( options , cha ) ; Util . addDefaultBypassLogic ( options , scope , Util . class . getClassLoader ( ) , cha ) ; if ( oldMethodTargetSelector != null ) { options . setSelector ( new WalaPointsToUtil . DelegatingMethodTargetSelector ( oldMethodTargetSelector , options . getMethodTargetSelector ( ) , scope ) ) ; } } final SSAContextInterpreter contextInterpreter ; if ( additionalContextInterpreter == null ) { contextInterpreter = new FallbackContextInterpreter ( new com . ibm . wala . ipa . callgraph . propagation . cfa . DefaultSSAInterpreter ( options , cache ) ) ; } else { <START_BUG> contextInterpreter = additionalContextInterpreter ; <END_BUG> } final int instancePolicy = ( ( ( ZeroXInstanceKeys . ALLOCATIONS ) | ( ZeroXInstanceKeys . CONSTANT_SPECIFIC ) ) | ( ZeroXInstanceKeys . SMUSH_MANY ) ) | ( ZeroXInstanceKeys . SMUSH_THROWABLES ) ; return ZeroXCFABuilder . make ( cha , options , cache , contextSelector , contextInterpreter , instancePolicy ) ; } public static CallGraphBuilder makeObjectSens ( final ExtendedAnalysisOptions options , final AnalysisCache cache , final IClassHierarchy cha , final AnalysisScope scope , final ContextSelector additionalContextSelector , final SSAContextInterpreter additionalContextInterpreter ) { } public static CallGraphBuilder makeNCallStackSens ( final int n , final AnalysisOptions options , final AnalysisCache cache , final IClassHierarchy cha , final AnalysisScope scope , final ContextSelector additionalContextSelector , final SSAContextInterpreter additionalContextInterpreter ) { } public static CallGraphBuilder makeNCallStackSens ( final int n , final AnalysisOptions options , final AnalysisCache cache , final IClassHierarchy cha , final AnalysisScope scope ) { } public static CallGraphBuilder makeContextFreeType ( final AnalysisOptions options , final AnalysisCache cache , final IClassHierarchy cha , final AnalysisScope scope ) { } public static CallGraphBuilder makeContextSensSite ( final AnalysisOptions options , final AnalysisCache cache , final IClassHierarchy cha , final AnalysisScope scope ) { } public static CallGraphBuilder makeObjectSens ( final ExtendedAnalysisOptions options , final AnalysisCache cache , final IClassHierarchy cha , final AnalysisScope scope ) { } }

Fix:
contextInterpreter = new com . ibm . wala . ipa . callgraph . propagation . cfa . DelegatingSSAContextInterpreter ( additionalContextInterpreter , new FallbackContextInterpreter ( new com . ibm . wala . ipa . callgraph . propagation . cfa . DefaultSSAInterpreter ( options , cache ) ) ) ;